Pedophilia once was thought to stem from psychological influences early in life. Now, many experts view it as a deep-rooted predisposition that does not change.
As a young boy, Paul Christiano loved the world of girls — the way they danced, how their spindly bodies tumbled in gymnastics.

In adolescence, as other boys ogled classmates, he was troubled to find himself fantasizing about 7- to 11-year-olds.

His desires remained stuck in time as he neared adulthood. Despite a stable home life in suburban Chicago, he was tortured by urges he knew could land him in prison.

"For having these feelings, I was destined to become a monster," he said. "I was terrified."

In 1999, Christiano was caught buying child pornography. Now 36, he said he has never molested a child, but after five years of state-ordered therapy, the attraction remains.

"These people felt they could snuff out the desire, or shame me into denying it existed," he said. "But it's as intrinsic as the next person's heterosexuality."

In the laboratory, researchers are coming to the same conclusion.

Like many forms of sexual deviance, pedophilia once was thought to stem from psychological influences early in life. Now, many experts view it as a sexual orientation as immutable as heterosexuality or homosexuality. It is a deep-rooted predisposition — limited almost entirely to men — that becomes clear during puberty and does not change.

The best estimates are that between 1% and 5% of men are pedophiles, meaning that they have a dominant attraction to prepubescent children.